Excerpts from Books and Wikipedia
"In the summer of 1866, some 400,000 men prepared for battle. At stake was the future of Germany. At that time, 39 states constituted a loose German Confederation, dominated by the Austrian Empire and the kingdom of Prussia, Prussian Chancellor Otto von Bismarck maneuvered Austria into a war he was confident the Prussian army could win. . . . But the Prussian soldiers were armed with Dreyse rifles, capable of five times the rate of fire of the Austrian arms. The Austrians had already suffered heavy casualties when the Prussian assault on their flank struck home. From then onward the issue was beyond doubt. The Austrians lost 45,000 men, compared with 9,000 Prussian casualties. Austria was in no condition to fight on, and an armistice was arranged. The peace treaty gave Prussia control of northern Germany, and excluded Austria from German affairs. A giant step had been taken toward a Prussian-dominated united Germany." [Furtado: 1001 Days] "Although some of the Prussian generals wanted to pursue and completely destroy the Austrian army, Bismarck astutely realized that, in the long run, it would be more useful to reconcile with Austria rather than to have her as a bitter enemy;" [Aldrete: Decisive Battles]